U.S. patent number 11,371,761 [Application Number 16/846,791] was granted by the patent office on 2022-06-28 for method of operating an air conditioner unit based on airflow.
This patent grant is currently assigned to Haier US Appliance Solutions, Inc.. The grantee listed for this patent is Haier US Appliance Solutions, Inc.. Invention is credited to Joshua Duane Longenecker.
United States Patent |
11,371,761 |
Longenecker |
June 28, 2022 |
Method of operating an air conditioner unit based on airflow
Abstract
A method of operating an air conditioner unit, as provided
herein, includes initiating a first heat pump cycle, the first heat
pump cycle comprising sending a control signal to the fan to rotate
at a predetermined rotational speed, and detecting an actual
rotational speed of the fan, calculating a first flow rate of air
through the first heat exchanger based on the control signal and
the actual rotational speed, storing the first flow rate as a first
reference flow rate, stopping the first heat pump cycle, initiating
a second heat pump cycle, calculating a second flow rate of air
through the first heat exchanger, comparing the calculated second
flow rate to the first reference flow rate, and directing the air
conditioner unit based on the comparison of the calculated second
flow rate to the first reference flow rate.
Inventors: |
Longenecker; Joshua Duane
(Louisville, KY) |
Applicant: |
Name |
City |
State |
Country |
Type |
Haier US Appliance Solutions, Inc. |
Wilmington |
DE |
US |
|
|
Assignee: |
Haier US Appliance Solutions,
Inc. (Wilmington, DE)
|
Family
ID: |
1000006397209 |
Appl.
No.: |
16/846,791 |
Filed: |
April 13, 2020 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20210318043 A1 |
Oct 14, 2021 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B
47/02 (20130101); F25B 47/025 (20130101); F25B
2700/173 (20130101); F25B 2700/135 (20130101) |
Current International
Class: |
F25B
47/02 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Diaz; Miguel A
Attorney, Agent or Firm: Dority & Manning, P.A.
Claims
What is claimed is:
1. A method of operating an air conditioner unit comprising a first
heat exchanger, a fan, and a controller, the method comprising:
initiating a first heat pump cycle, the first heat pump cycle
comprising: sending a control signal to the fan to rotate at a
predetermined rotational speed, and detecting an actual rotational
speed of the fan; calculating a first flow rate of air through the
first heat exchanger based on the control signal and the actual
rotational speed; storing the first flow rate as a first reference
flow rate; stopping the first heat pump cycle; initiating a second
heat pump cycle; calculating a second flow rate of air through the
first heat exchanger; comparing the calculated second flow rate to
the first reference flow rate; and directing the air conditioner
unit based on the comparison of the calculated second flow rate to
the first reference flow rate.
2. The method of claim 1, wherein the actual rotational speed is
detected by a rotational speed sensor provided on the fan.
3. The method of claim 1, wherein the first heat pump cycle further
comprises circulating a refrigerant through a sealed refrigerant
system in a first direction, the sealed refrigerant system
comprising a compressor, the first heat exchanger, an expansion
device, and a second heat exchanger.
4. The method of claim 3, wherein comparing the calculated second
flow rate to the first reference flow rate comprises determining
the calculated second flow rate is less than the first reference
flow rate by a predetermined threshold, wherein directing the air
conditioner unit comprises initiating a defrost cycle comprising
activating a heater bank directed at the first heat exchanger.
5. The method of claim 3, wherein comparing the calculated second
flow rate to the first reference flow rate comprises determining
the calculated second flow rate is less than the first reference
flow rate by a first predetermined threshold, wherein directing the
air conditioner unit comprises initiating a defrost cycle at the
sealed refrigerant system.
6. The method of claim 5, wherein the defrost cycle comprises
circulating the refrigerant through the sealed refrigerant system
in a second direction opposite the first direction.
7. The method of claim 5, wherein the defrost cycle comprises
activating a heater bank directed at the first heat exchanger.
8. The method of claim 5, further comprising: stopping the defrost
cycle; initiating a third heat pump cycle; calculating a third flow
rate of air through the first heat exchanger based on the control
signal and the actual rotational speed during the third heat pump
cycle; storing the third flow rate as a second reference flow rate
in place of the first reference flow rate; initiating a fourth heat
pump cycle; calculating a fourth flow rate of air through the first
heat exchanger; comparing the calculated fourth flow rate to the
second reference flow rate; and directing the air conditioner unit
based on the comparison of the calculated second flow rate to the
second reference flow rate.
9. The method of claim 8, wherein comparing the calculated fourth
flow rate to the second reference flow rate comprises determining
the calculated fourth flow rate is less than the second reference
flow rate by a second predetermined threshold, wherein directing
the air conditioner unit comprises initiating the defrost cycle at
the sealed refrigerant system.
10. The method of claim 9, wherein the second predetermined
threshold is a threshold percentage of 50% of the first reference
flow rate or the second reference flow rate.
11. An air conditioner unit, comprising: a sealed refrigerant
system comprising a refrigerant conduit, a first heat exchanger, an
expansion device, and a second heat exchanger in fluid
communication with each other along the refrigerant conduit, and a
compressor to drive a refrigerant through the sealed refrigerant
system; a fan located adjacent to the first heat exchanger to
circulate air over the first heat exchanger; and a controller
configured to initiate an operation sequence, the operation
sequence comprising: initiating a heat pump cycle, the heat pump
cycle comprising: sending a control signal to the fan to rotate at
a predetermined rotational speed, and detecting an actual
rotational speed of the fan; calculating a first flow rate of air
through the heat exchanger based on the control signal and the
actual rotational speed; storing the first flow rate as a first
reference flow rate; stopping the heat pump cycle; initiating a
second heat pump cycle; calculating a second flow rate of air
through the first heat exchanger; comparing the calculated second
flow rate to the first reference flow rate; and directing the air
conditioner unit based on the comparison of the calculated second
flow rate to the first reference flow rate.
12. The air conditioner unit of claim 11, wherein the actual
rotational speed is detected by a rotational speed sensor provided
on the fan.
13. The air conditioner unit of claim 11, wherein refrigerant is
circulated through the sealed refrigerant system in a first
direction.
14. The air conditioner unit of claim 13, wherein comparing the
calculated second flow rate to the first reference flow rate
comprises determining the calculated second flow rate is less than
the first reference flow rate by a predetermined threshold, wherein
directing the air conditioner unit comprises initiating a defrost
cycle comprising activating a heater bank directed at the first
heat exchanger.
15. The air conditioner unit of claim 13, wherein comparing the
calculated second flow rate to the first reference flow rate
comprises determining the calculated second flow rate is less than
the first reference flow rate by a first predetermined threshold,
wherein directing the air conditioner unit comprises initiating a
defrost cycle at the sealed refrigerant system.
16. The air conditioner unit of claim 15, wherein the defrost cycle
comprises circulating the refrigerant through the sealed
refrigerant system in a second direction opposite the first
direction.
17. The air conditioner unit of claim 15, wherein the defrost cycle
comprises activating a heater bank directed at the first heat
exchanger.
18. The air conditioner unit of claim 15, wherein the operation
sequence further comprises: stopping the defrost cycle; initiating
a third heat pump cycle; calculating a third flow rate of air
through the first heat exchanger based on the control signal and
the actual rotational speed during the third heat pump cycle;
storing the third flow rate as a second reference flow rate in
place of the first reference flow rate; initiating a fourth heat
pump cycle; calculating a fourth flow rate of air through the first
heat exchanger; comparing the calculated fourth flow rate to the
second reference flow rate; and directing the air conditioner unit
based on the comparison of the calculated second flow rate to the
second reference flow rate.
19. The air conditioner unit of claim 18, wherein comparing the
calculated fourth flow rate to the second reference flow rate
comprises determining the calculated fourth flow rate is less than
the second reference flow rate by a second predetermined threshold,
wherein directing the air conditioner unit comprises initiating the
defrost cycle at the sealed refrigerant system.
20. The air conditioner unit of claim 19, wherein the second
predetermined threshold is a threshold percentage of 50% of the
first reference flow rate or the second reference flow rate.
Description
FIELD OF THE INVENTION
The present subject matter relates generally to air conditioner
units, and more particularly to methods of operation and frost
detection on air conditioning units.
BACKGROUND OF THE INVENTION
Air conditioner units are conventionally utilized to adjust the
temperature within structures such as dwellings and office
buildings. In particular, one-unit type or single-package air
conditioner units, such as window units, single-package vertical
units (SPVU), vertical packaged air conditioners (VPAC), or package
terminal air conditioners (PTAC) may be utilized to adjust the
temperature in, for example, a single room or group of rooms of a
structure. Such units are especially common in hotels, rental
apartments, and assisted-living facilities in which a large number
of occupants live within the same building.
A typical one-unit type air conditioner unit or air conditioning
appliance includes an indoor portion and an outdoor portion. The
indoor portion generally communicates (e.g., exchanges air) with
the area within a building, and the outdoor portion generally
communicates (e.g., exchanges air) with the area outside a
building. Accordingly, the air conditioner unit generally extends
through, for example, a wall of the structure. Generally, a fan may
be operable to rotate to motivate air through the indoor portion.
Another fan may be operable to rotate to motivate air through the
outdoor portion. A sealed cooling system including a compressor is
generally housed within the air conditioner unit to treat (e.g.,
cool or heat) air as it is circulated through, for example, the
indoor portion of the air conditioner unit. One or more control
boards are typically provided to direct the operation of various
elements of the particular air conditioner unit.
When a typical one-unit air conditioner unit operates during a cold
outdoor condition, frost may be generated on a heat exchange coil
of the outdoor portion. This frost is difficult to detect using
temperature sensors alone. For instance, a conventional air
conditioner unit may utilize an exterior air temperature sensor to
simply measure a condition in which frost might form. Consequently,
conventional air conditioner units are inefficient in running
defrost cycles (e.g., defrost cycles are run too often or not
enough). Specifically, exterior air temperature sensors may give
false readings and incorrectly detect frost on a conventional air
conditioner unit and thus unnecessarily run a defrost cycle. This
in turn wastes electricity and energy. Similarly, other methods of
detecting frost on conventional air conditioner units, such as air
flow sensors or refrigerant temperature sensors, may also give
trigger false indications of a presence of frost.
Accordingly, it may be useful to provide an air conditioner unit
addressing one or more of the above-identified issues. In
particular, it may be advantageous to provide an air conditioner
unit or method of operation that can detect frost in a more
accurate or efficient way.
BRIEF DESCRIPTION OF THE INVENTION
Aspects and advantages of the invention will be set forth in part
in the following description, or may be obvious from the
description, or may be learned through practice of the
invention.
In one exemplary aspect of the present disclosure, a method of
operating an air conditioner is provided. The method may include
initiating a first heat pump cycle, which may include sending a
control signal to the fan to rotate at a predetermined rotational
speed and detecting an actual rotational speed of the fan. The
method may further include calculating a first flow rate of air
through the first heat exchanger based on the control signal and
the actual rotational speed, storing the first flow rate as a first
reference flow rate, stopping the first heat pump cycle, and
initiating a second heat pump cycle. The method may still further
include calculating a second flow rate of air through the first
heat exchanger, comparing the calculated second flow rate to the
first reference flow rate, and directing the air conditioner unit
based on the comparison of the calculated second flow rate to the
first reference flow rate.
In another exemplary embodiment of the present disclosure, an air
conditioner unit is provided. The air conditioner unit may include
a sealed refrigerant system comprising a refrigerant conduit, a
first heat exchanger, an expansion device, and a second heat
exchanger in fluid communication with each other along the
refrigerant conduit, and a compressor to drive a refrigerant
through the sealed refrigerant system, a fan located adjacent to
the first heat exchanger to circulate air over the first heat
exchanger, and a controller configured to initiate an operation
sequence. The operation sequence may include initiating a heat pump
cycle, the heat pump cycle comprising sending a control signal to
the fan to rotate at a predetermined rotational speed, and
detecting an actual rotational speed of the fan; calculating a
first flow rate of air through the heat exchanger based on the
control signal and the actual rotational speed; storing the first
flow rate as a first reference flow rate; and stopping the heat
pump cycle. The operation sequence may further include initiating a
second heat pump cycle; calculating a second flow rate of air
through the first heat exchanger; comparing the calculated second
flow rate to the first reference flow rate; and directing the air
conditioner unit based on the comparison of the calculated second
flow rate to the first reference flow rate.
These and other features, aspects and advantages of the present
invention will become better understood with reference to the
following description and appended claims. The accompanying
drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the invention and,
together with the description, serve to explain the principles of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
A full and enabling disclosure of the present invention, including
the best mode thereof, directed to one of ordinary skill in the
art, is set forth in the specification, which makes reference to
the appended figures.
FIG. 1 provides a perspective view of an air conditioner unit, with
a room front exploded from a remainder of the air conditioner unit
for illustrative purposes, in accordance with exemplary embodiments
of the present disclosure.
FIG. 2 is a perspective view of components of an indoor portion of
an air conditioner unit in accordance with exemplary embodiments of
the present disclosure.
FIG. 3 provides a schematic view of an air conditioner unit
according to exemplary embodiments of the present disclosure.
FIG. 4 provides a flow chart illustrating a method of operating an
air conditioner unit according to exemplary embodiments of the
present disclosure.
DETAILED DESCRIPTION
Reference now will be made in detail to embodiments of the
invention, one or more examples of which are illustrated in the
drawings. Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the scope of the invention. For instance, features illustrated
or described as part of one embodiment can be used with another
embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
As used herein, the term "or" is generally intended to be inclusive
(i.e., "A or B" is intended to mean "A or B or both"). The phrase
"in one embodiment," does not necessarily refer to the same
embodiment, although it may. The terms "first," "second," and
"third" may be used interchangeably to distinguish one component
from another and are not intended to signify location or importance
of the individual components. The terms "upstream" and "downstream"
refer to the relative flow direction with respect to fluid flow in
a fluid pathway. For example, "upstream" refers to the flow
direction from which the fluid flows, and "downstream" refers to
the flow direction to which the fluid flows.
Referring now to the figures, in FIGS. 1 through 3, an air
conditioner or air conditioner unit 10 according to various
exemplary embodiments is provided. The air conditioner 10 is
generally a one-unit type air conditioner, also conventionally
referred to as a room air conditioner or package terminal air
conditioner unit (PTAC). The air conditioner 10 includes an indoor
portion 12 and an outdoor portion 14, and defines a vertical
direction V, a lateral direction L, and a transverse direction T.
Each direction V, L, T is perpendicular to each other, such that an
orthogonal coordinate system is generally defined.
Although described in the context of a PTAC, an air conditioner
unit as disclosed herein may be provided as a window unit,
single-package vertical unit (SPVU), vertical packaged air
conditioner (VPAC), or any other suitable single-package air
conditioner. The air conditioner 10 is intended only as an
exemplary unit and does not otherwise limit the scope of the
present disclosure. Thus, it is understood that the present
disclosure may be equally applicable to other types of air
conditioner units.
Generally, a cabinet 20 of the air conditioner 10 contains various
other components of the air conditioner 10. Cabinet 20 may include,
for example, a rear grill 22 and a room front 24 that may be spaced
apart along the transverse direction T by a wall sleeve 26. The
rear grill 22 may be part of the outdoor portion 14, while the room
front 24 is part of the indoor portion 12. Components of the
outdoor portion 14, such as an outdoor heat exchanger 30, outdoor
fan 33, and compressor 32 may be housed within the wall sleeve 26.
A casing 34 may additionally enclose the outdoor fan 33, as shown.
In one example, outdoor fan 33 is powered by a DC voltage fan
motor. However, it should be appreciated that any suitable motor
may be used to power outdoor fan 33.
Indoor portion 12 may include, for example, an indoor heat
exchanger 40, a blower fan 42, and a (e.g., first) heating unit 44.
These components may, for example, be housed behind the room front
24. Additionally, a bulkhead 46 may generally support or house
various other components or portions thereof of the indoor portion
12, such as the blower fan 42 and the heating unit 44. Bulkhead 46
may generally separate and define the indoor portion 12 and outdoor
portion 14.
Outdoor and indoor heat exchangers 30, 40 may be components of a
thermodynamic assembly (i.e., sealed system), which may be operated
as a refrigeration assembly (and thus perform a refrigeration cycle
in a cooling mode) and, in the case of the heat pump unit
embodiment, a heat pump (and thus perform a heat pump cycle in a
heating mode). Thus, as is understood, exemplary heat pump unit
embodiments may be selectively operated perform a refrigeration
cycle at certain instances (e.g., while in a cooling mode) and a
heat pump cycle at other instances (e.g., while in a heating mode).
By contrast, exemplary A/C exclusive unit embodiments may be unable
to perform a heat pump cycle (e.g., while in the heating mode), but
still perform a refrigeration cycle (e.g., while in a cooling
mode).
In optional embodiments, such as exemplary heat pump unit
embodiments, the sealed system includes a reversible refrigerant
valve 110. Reversible refrigerant valve 110 selectively directs
compressed refrigerant from compressor 32 to either indoor heat
exchanger 40 or outdoor heat exchanger 30. For example, in a
cooling mode, reversible refrigerant valve 110 is arranged or
configured to direct compressed refrigerant from compressor 32 to
outdoor heat exchanger 30. Conversely, in a heating mode,
reversible refrigerant valve 110 is arranged or configured to
direct compressed refrigerant from compressor 32 to indoor heat
exchanger 40. Thus, reversible refrigerant valve 110 permits the
sealed system to adjust between the heating mode and the cooling
mode, as will be understood by those skilled in the art.
The sealed system or assembly may, for example, further include
compressor 32 and an expansion device 38, both of which may be in
fluid communication with the heat exchangers 30, 40 to flow
refrigerant therethrough, as is generally understood. Expansion
device 38 may be any suitable expansion device, such as a
mechanical valve, capillary tube, electronic expansion valve, or
other restriction device, for example. Optionally, the compressor
32 may be a variable speed compressor or, alternatively, a single
speed compressor. When the assembly is operating in a cooling mode,
and thus performs a refrigeration cycle, the indoor heat exchanger
40 acts as an evaporator and the outdoor heat exchanger 30 acts as
a condenser. In heat pump unit embodiments, when the assembly is
operating in a heating mode, and thus performs a heat pump cycle,
the indoor heat exchanger 40 acts as a condenser and the outdoor
heat exchanger 30 acts as an evaporator. The outdoor and indoor
heat exchangers 30, 40 may each include coils 31, 41, as
illustrated, through which a refrigerant may flow for heat exchange
purposes, as is generally understood. For instance, and as will be
understood, in response to an input temperature setting, compressor
32 may activate for a cycle (e.g., cooling cycle or heating cycle)
until the input temperature setting (or hysteresis thereof) is
detected within the corresponding room.
Bulkhead 46 may include various peripheral surfaces that define an
interior 50 thereof. For example, bulkhead 46 may include a first
sidewall 52 and a second sidewall 54 which are spaced apart from
each other along the lateral direction L. A rear wall may extend
laterally between the first sidewall 52 and second sidewall 54.
Bulkhead 46 may additionally include, for example, an air diverter
68, which may extend between the sidewalls 52, 54 along the lateral
direction L and through which air may flow.
In exemplary embodiments, blower fan 42 may be a tangential fan.
Alternatively, however, any suitable fan type may be utilized.
Blower fan 42 may include a blade assembly 70 and a motor 72. The
blade assembly 70, which may include one or more blades disposed
within a fan housing 74, may be disposed at least partially within
the interior 50 of the bulkhead 46, such as within the upper
portion. As shown, blade assembly 70 may for example extend along
the lateral direction L between the first sidewall 52 and the
second sidewall 54. The motor 72 may be connected to the blade
assembly 70, such as through the fan housing 74 to the blades via a
shaft. Operation of the motor 72 may rotate the blades, thus
generally operating the blower fan 42 (e.g., in a cooling mode,
heating mode, or fan-only mode). Further, in exemplary embodiments,
motor 72 may be disposed exterior to the bulkhead 46. Accordingly,
the shaft may for example extend through one of the sidewalls 52,
54 to connect the motor 72 and blade assembly 70.
In exemplary embodiments, heating unit 44 includes one or more
heater banks 80. Each heater bank 80 may be operated as desired to
produce heat. In some embodiments, three heater banks 80 may be
utilized, as shown. Alternatively, however, any suitable number of
heater banks 80 may be utilized. Each heater bank 80 may further
include at least one heater coil or coil pass 82, such as in
exemplary embodiments two heater coils or coil passes 82.
Alternatively, other suitable heating elements may be utilized. As
is understood, each heater coil pass 82 may be provided as a
resistive heating element configured to generate heat in response
to resistance to an electrical current flowed therethrough. For
instance, and as will be understood, in response to an input
temperature setting, at least a portion of heater bank 82 may
activate as an electrical current is flowed therethrough for a
heating cycle until the input temperature setting (or hysteresis
thereof) is detected within the corresponding room.
The operation of air conditioner 10, including compressor 32 (and
thus the sealed system generally) blower fan 42, fan 33, heating
unit 44, and other suitable components, may be controlled by a
control board or controller 85. Controller 85 may be in
communication (via for example a suitable wired or wireless
connection) to such components of the air conditioner 10. By way of
example, the controller 85 may include a memory and one or more
processing devices such as microprocessors, CPUs or the like, such
as general or special purpose microprocessors operable to execute
programming instructions or micro-control code associated with
operation of air conditioner 10 (e.g., as or as part of a
conditioner operation). The memory may be a separate component from
the processor or may be included onboard within the processor. The
memory may represent random access memory such as DRAM, or read
only memory such as ROM or FLASH. Generally, the processor executes
programming instructions stored in memory.
Air conditioner 10 may additionally include a control panel 87 and
one or more user inputs 89, which may be included in control panel
87. The user inputs 89 may be in communication with the controller
85. A user of the air conditioner 10 may interact with the user
inputs 89 to operate the air conditioner 10, and user commands may
be transmitted between the user inputs 89 and controller 85 to
facilitate operation of the air conditioner 10 based on such user
commands (e.g., to specify a desired temperature, cooling mode,
heating mode, fan-only mode, idle mode, date/time, service event,
etc.). A display 88 may additionally be provided in the control
panel 87 and may be in communication with the controller 85.
Display 88 may, for example be a touchscreen or other text-readable
display screen, or alternatively may simply be a light that can be
activated and deactivated as required to provide an indication of,
for example, an event, setting, or mode for the air conditioner
10.
In some embodiments, a first indoor temperature sensor 92 (e.g.,
indoor refrigerant temperature sensor) or a second indoor
temperature sensor 94 (e.g., indoor ambient temperature sensor) is
disposed within the indoor portion 12. In optional embodiments, a
third indoor temperature sensor 126 (e.g., indoor outlet
temperature sensor) (as indicated in phantom lines) is disposed
within the indoor portion 12. In alternative embodiments, indoor
portion 12 is free of any such third indoor temperature sensor 126.
Each temperature sensor may be configured to sense the temperature
of its surroundings. For example, each temperature sensor may be a
thermistor or a thermocouple. The indoor temperature sensors 92,
94, 126 may be in communication with the controller 85, and may
transmit temperatures sensed thereby to the controller 85 (e.g., as
one or more voltages or signals, which the controller 85 is
configured to interpret as temperature values). Optionally, the
voltages or signal transmitted to the controller 85 may be
transmitted in response to a polling request or signal received by
one or more of the indoor temperature sensors 92, 94, 126. For
example, a polling request or signal may be transmitted to one or
more of the indoor temperature sensors 92, 94, 126 from the
controller 85.
First indoor temperature sensor 92 may be disposed proximate to the
indoor heat exchanger 40 (such as relative to the second indoor
temperature sensor 94). For example, in some embodiments, first
indoor temperature sensor 92 may be in contact with the indoor heat
exchanger 40, such as with a coil 41 thereof. The first indoor
temperature sensor 92 may be configured to detect a temperature for
the indoor heat exchanger 40. Second indoor temperature sensor 94
may be spaced from the indoor heat exchanger 40, such as in the
transverse direction T. For example, the second indoor temperature
sensor 94 may be in contact with the room front 24, as illustrated
in FIG. 1. Second indoor temperature sensor 94 may be configured to
detect a temperature of air entering the indoor portion 12. Third
indoor temperature sensor 126 may be spaced apart from and disposed
downstream of both the first indoor temperature sensor 92 and the
second indoor temperature sensor 94. For example, the third indoor
temperature sensor 126 may be attached to or in contact with the
air diverter 68. The third indoor temperature sensor 126 may be
configured to detect a temperature for air exiting the indoor
portion 12. During certain operations (e.g., in a cooling mode),
air may thus generally flow across or adjacent to the second indoor
temperature sensor 94, the first indoor temperature sensor 92, and
then the third indoor temperature sensor 126.
As shown, outdoor heat exchanger 30 may further include an outdoor
(e.g., second) heating unit 112 provided at or near coils 31 of
outdoor heat exchanger 30. Second heating unit 112 may be similar
to heating unit 44. For instance, second heating unit 112 may
include one or more heater banks 114. Each heater bank 114 may be
operated as desired to produce heat to heat coils 31 of outdoor
heat exchanger 30. In some embodiments, three heater banks 114 may
be utilized, as shown. Alternatively, however, any suitable number
of heater banks 114 may be utilized. Each heater bank 114 may
further include at least one heater coil or coil pass.
Alternatively, other suitable heating elements may be utilized. As
is understood, each heater coil pass may be provided as a resistive
heating element configured to generate heat in response to
resistance to an electrical current flowed therethrough.
Outdoor heat exchanger 30 may further include a rotational speed
sensor 134 (e.g., in communication with controller 85). Generally,
the rotational speed sensor 134 may be configured measure a
rotational speed (e.g., revolutions per minute RPM) of outdoor fan
33 and send the resulting measurement to controller 85. The
rotational speed sensor may be any suitable sensor capable of
measuring a rotational speed of outdoor fan 33, for instance a
tachometer, an opto-isolator, or a Hall sensor. The rotational
speed sensor 134 may be provided on outdoor fan 33, or
alternatively, adjacent to outdoor fan 33 so as to accurately
measure a rotational speed of outdoor fan 33.
Referring now to FIG. 4, the present disclosure may further be
directed to methods (e.g., method 400) of operating an air
conditioner unit, such as air conditioner unit 10. In exemplary
embodiments, controller 85 may be operable to perform various steps
of a method in accordance with the present disclosure.
The methods (e.g., 400) may occur as, or as part of, a conditioner
operation (e.g., a cooling or heating operation) of the air
conditioner 10. In particular, the methods disclosed herein may
advantageously facilitate the accurate or efficient detection of
frost, such as at or on outdoor heat exchanger 30. Additionally or
alternatively, the methods disclosed herein may permit frost
detection without the need of (e.g., without requiring) any
temperature sensors or temperature measurements at outdoor portion
14.
At 410, the method 400 includes initiating a first heat pump cycle.
Specifically, the controller may send a signal to operate the
compressor to compress a refrigerant and circulate the refrigerant
through the corresponding sealed system. For example, refrigerant
may be motivated by the compressor through the reversible
refrigerant valve, a first heat exchanger (e.g., the indoor heat
exchanger), the expansion device, a second heat exchanger (e.g.,
the outdoor heat exchanger), and back through the reversible
refrigerant valve. In the first heat pump cycle, the refrigerant
may be circulated in a first direction. In some embodiments, the
first direction includes circulating the refrigerant first through
the indoor heat exchanger, followed by the expansion device and the
outdoor heat exchanger. In such embodiments, the indoor heat
exchanger functions as a condenser and the outdoor heat exchanger
functions as an evaporator. In alternative embodiments, the first
direction includes circulating the refrigerant first through the
outdoor heat exchanger, followed by the expansion device and the
indoor heat exchanger. In this embodiment, the outdoor heat
exchanger functions as a condenser and the indoor heat exchanger
functions as an evaporator.
At 412, the method 400 includes sending a first control or voltage
signal to the outdoor fan to rotate at a predetermined rotational
speed. The predetermined rotational speed may be an intended speed
or setting at which the outdoor fan is to rotate according to the
controller. In other words, the predetermined rotational speed may
be a target rotational speed setting (e.g., provided as part of an
automatic or controller-directed feedback loop) as determined by
the controller to circulate enough air through the outdoor heat
exchanger to produce a desired indoor temperature. The controller
may alter the first control signal to the outdoor fan in order to
rotate the outdoor fan at the predetermined rotational speed. The
first control signal may vary depending on a power of the outdoor
fan (e.g., motor size and type), an amount of air required to pass
over the coils of the outdoor heat exchanger, or the like.
At 414, the method 400 includes detecting a first actual rotational
speed of the outdoor fan. For example, the rotational speed sensor
may sense a first rotational speed of the outdoor fan after the
outdoor fan receives the first control signal from the controller
at 412. The rotational speed sensor may then send the resultant
measurement to the controller (e.g., to be stored in the memory
portion of the controller). The actual rotational speed of the
outdoor fan may be a measured rotational speed and may, under
certain conditions, differ from the predetermined rotational speed.
For example, the second control signal from the controller may be
higher than the first control signal in order to have the fan
rotate at the predetermined rotational speed if the outdoor heat
exchanger is dirty (e.g., covered in dust or debris) or coated with
frost.
At 416, the method 400 includes calculating a first flow rate of
air through the first heat exchanger (e.g., the outdoor heat
exchanger) based on the control signal and the actual rotational
speed. The first flow rate may also be calculated including a unit
voltage of the fan motor. For instance, the controller may perform
a calculation including the unit voltage of the fan motor, the
control signal sent to the fan motor, and the actual rotational
speed of the outdoor fan (e.g., as sensed by the rotational speed
sensor). The flow rate may be a volumetric flow rate.
Alternatively, the flow rate may be a mass flow rate or any other
suitable flow rate.
In alternative embodiments, the controller may perform a
calculation including two variables out of the group of the unit
voltage of the fan motor, the voltage signal sent to the fan motor,
and the actual rotational speed of the outdoor fan. The controller
may be preprogrammed with a function or series of functions or
formulas configured to calculate the flow rate. As example function
is provided below:
Flow=A+B*RPM+C*CS+D*Voltage+E*RPM.sup.2+F*CS.sup.2+G*Voltage.sup.2+H*RPM*-
CS+I*CS*Voltage+J*Voltage *RPM where "CS" is the control signal and
variables A through J are experimental coefficients determined
through testing a representative model of an exemplary air
conditioning unit.
In still other embodiments, the controller may perform a
calculation using a square or cube of the group of variables. For
instance, the unit voltage may be squared or cubed, the voltage
signal may be squared or cubed, or the actual rotational speed of
the outdoor fan may be squared or cubed. However, it is understood
that other functions or formulas may be used in conjunction with
or, alternatively to, the example function given above.
At 418, the method 400 includes storing the first flow rate as a
first reference flow rate. For instance, the controller may store
the calculated first flow rate as a reference flow rate (e.g.,
within a reference flow rate cell or placeholder of memory). In
some embodiments, the first reference flow rate can act as or be
understood as a flow rate of air over the coils of the outdoor heat
exchanger in a frost-free state (e.g., when there is no frost
present on the coils).
At 420, the method 400 includes stopping the first heat pump cycle.
In other words, the controller may stop an operation of the
compressor and subsequently a circulation of refrigerant. Any
suitable signal may be used to signal the controller to stop the
first heat pump cycle. For instance, a time limit may be input by a
user into the controller to stop the first heat pump cycle after a
predetermined amount of time. In additional or alternative
embodiments, the second indoor temperature sensor is configured to
continually measure a temperature of an interior room in which the
indoor portion is situated. The controller may then stop the first
heat pump cycle when an ambient temperature of the interior room
meets or exceeds a predetermined temperature input by the user.
According to some such embodiments, when the air conditioner unit
is operating in a heating mode (i.e., the indoor heat exchanger
functions as a condenser and the outdoor heat exchanger functions
as an evaporator), the controller is configured stop the first heat
pump cycle when the temperature of the interior room rises above
the predetermined temperature.
At 422, the method 400 includes initiating a second heat pump cycle
(e.g., following or subsequent to 420). Similar to the first heat
pump cycle, the controller may send a signal to operate the
compressor to compress a refrigerant and circulate the refrigerant
through the corresponding sealed system. For example, refrigerant
may be motivated by the compressor through the reversible
refrigerant valve, the first heat exchanger (e.g., the indoor heat
exchanger), the expansion device, the second heat exchanger (e.g.,
the outdoor heat exchanger), and back through the reversible
refrigerant valve. In the second heat pump cycle, the refrigerant
may be circulated in the first direction. In some embodiments, the
first direction includes circulating the refrigerant first through
the indoor heat exchanger, followed by the expansion device and the
outdoor heat exchanger. In such embodiments, the indoor heat
exchanger functions as a condenser and the outdoor heat exchanger
functions as an evaporator. In alternative embodiments, the first
direction includes circulating the refrigerant first through the
outdoor heat exchanger, followed by the expansion device and the
indoor heat exchanger. In this embodiment, the outdoor heat
exchanger functions as a condenser and the indoor heat exchanger
functions as an evaporator.
At 424, the method 400 includes calculating a second flow rate of
air through the first heat exchanger (e.g., during the second heat
pump cycle). The calculation of the second flow rate of air through
the first heat exchanger may include a sending a second control
signal to the outdoor fan to operate at the predetermined
rotational speed. The predetermined rotational speed may be an
intended speed at which the outdoor fan is to rotate according to
the controller. In other words, the predetermined rotational speed
is a target rotational speed as determined by the controller to
circulate enough air through the outdoor heat exchanger to produce
a desired indoor temperature.
The controller may alter the second control signal to the outdoor
fan in order to rotate the outdoor fan at the predetermined
rotational speed. The second voltage signal may vary depending on a
power of outdoor fan (i.e., motor size and type), an amount of air
required to pass over the coils of the outdoor heat exchanger, or
the like. The calculation of the second flow rate of air through
the first heat exchanger may also include detecting a second actual
rotational speed of the outdoor fan. The rotational speed sensor
may sense a second rotational speed of the outdoor fan after the
outdoor fan receives the second control signal from the controller.
The rotational speed sensor may then send the resultant measurement
back to the controller to be stored in the memory portion of the
controller. The actual rotational speed of the outdoor fan may be a
measured rotational speed and may differ from the predetermined
rotational speed. For example, the second control signal from the
controller may be higher than the first control signal in order to
have the fan rotate at the predetermined rotational speed if the
outdoor heat exchanger is dirty (e.g., covered in dust or debris)
or coated with frost.
At 426, the method 400 includes comparing the calculated second
flow rate to the first reference flow rate. For example, the
controller may compare the calculated second flow rate to the first
reference flow rate and calculate a difference between the two
(e.g., a threshold percentage difference). In other words, the
calculated second flow rate may be stored as a certain percentage
of the first reference flowrate. From the comparison (e.g.,
according to the calculated difference), a determination may be
made as to whether the second flow rate is within a predetermined
threshold (e.g., a certain threshold percentage) relative to the
first reference flow rate. Optionally, the predetermined threshold
may be a percentage of 50% of the (e.g., first) reference flow
rate.
At 428, the method 400 includes directing the air conditioner unit
based on the comparison of the calculated second flow rate to the
first reference flow rate at 426. In some embodiments, the
controller analyzes a result of the comparison between the
calculated second flow rate and the first reference flow rate. If
the calculated second flow rate meets the predetermined threshold
of the first reference flow rate, the second heat pump cycle may
continue to run. Thus, the second heat pump cycle may be maintained
in response to a determination that the calculated second flow rate
is within the predetermined threshold (e.g., threshold percentage).
Optionally, the controller may then analyze whether to stop the
second heat pump cycle according to an alternative signal (e.g., an
interior temperature of the room, a time limit, etc.). Accordingly,
this may be referred to as a normal operation of the air
conditioner unit. In turn, second heat pump cycle may be run
continuously until the calculated second flow rate is less than the
first reference flow rate by a predetermined percentage threshold
(or operation is otherwise halted). Further, any number of
successive heat pump cycles may be run until the calculated second
flow rate does not meet the predetermined threshold of the first
reference flowrate.
If the calculated second flow rate is less than the first reference
flow rate by the predetermined threshold, the controller may stop
the second heat pump cycle (i.e., stop a circulation of the
refrigerant). Thus, the second heat pump cycle may be restricted or
stopped in response to a determination that the second flow rate is
less than the predetermined threshold (e.g., threshold percentage).
Additionally or alternatively, the controller may initiate a first
defrost cycle (e.g., subsequent to the second heat pump cycle being
stopped or otherwise in response to the determination that the
second flow rate is less than the predetermined threshold).
The first defrost cycle may include circulating the refrigerant in
a second direction opposite the first direction. For example,
circulating the refrigerant in the second direction may include
circulating the refrigerant first through the outdoor heat
exchanger, followed by the expansion device and the outdoor heat
exchanger. In this embodiment, high temperature refrigerant is
circulated through the outdoor heat exchanger and thus frost may be
melted from the coils. Additionally or alternatively, the defrost
cycle may include activating one or more of the heater banks (e.g.,
while maintaining the second heat pump cycle in a stopped state).
In optional embodiments, the defrost cycle includes simultaneously
circulating the refrigerant in the second direction and activating
one or more of the heater banks.
Following the defrost cycle, the coils of the outdoor heat
exchanger may be defrosted, and the normal operation of the air
conditioner unit may resume.
At 430, the method 400 includes directing subsequent heat pump
cycles. In some embodiments, 430 includes storing a third flow rate
as a second reference flow rate (e.g., in place of the first
reference flow rate). For instance, a third heat pump cycle may be
initiated after the defrost cycle is stopped (e.g., following the
defrost cycle or 428). The third heat pump cycle may be similar to
the first heat pump cycle or the second heat pump cycle described
above. For instance, to initiate the third heat pump cycle, the
controller may send a signal to operate the compressor to compress
a refrigerant and circulate the refrigerant through the
corresponding sealed system. For example, refrigerant may be
motivated by the compressor through the reversible refrigerant
valve, a first heat exchanger (e.g., the indoor heat exchanger),
the expansion device, a second heat exchanger (e.g., the outdoor
heat exchanger), and back through the reversible refrigerant valve.
During the third heat pump cycle, the controller may send a third
control signal to the outdoor fan to rotate at a predetermined
rotational speed (e.g., identical to or, alternatively, different
from the predetermined rotational speed of the first heat pump
cycle or the second heat pump cycle). The third control signal may
be similar to the first control signal described above. The
controller may detect a third actual rotational speed of the
outdoor fan. The third actual rotational speed may be similar to
the first actual rotational speed described above. The controller
may then stop the third heat pump cycle. Similar to the stopping of
the first heat pump cycle, any suitable signal may be used to
signal the controller to stop the third heat pump cycle. For
instance, a time limit may be input by a user into the controller
to stop the third heat pump cycle after a predetermined amount of
time. In additional or alternative embodiments, the second indoor
temperature sensor is configured to continually measure a
temperature of an interior room in which the indoor portion is
situated. The controller may then stop the third heat pump cycle
when an ambient temperature of the interior room meets or exceeds a
predetermined temperature input by the user.
After the third heat pump cycle is stopped, the controller may then
calculate a third flow rate according to the variables stored
during the third heat pump cycle. For example, the controller
calculates the third flow rate using the third control signal and
the third actual rotational speed of the outdoor fan. The
controller may use Equation 1 described above to calculate the
third flow rate. The third calculated flow rate may then be stored
as a second reference flow rate. In some such embodiments, the
second reference flow rate may replace, overwrite, or otherwise
take the place of the first reference flow rate. The second
reference flow rate may be different from the first reference flow
rate. For instance, during a normal operation of the first heat
pump cycle, the second heat pump cycle, and subsequent heat pump
cycles before the first defrost cycle, dirt or debris may build up
on the coils of the outdoor heat exchanger. This may alter a normal
air flow (e.g., a defrost-free airflow). As such, the calculated
third flow rate may be stored as the second reference flow rate in
place of the first reference flow rate to establish a new reference
flow rate.
Following the third heat pump cycle, the method 400 may include
initiating a fourth heat pump cycle. The fourth heat pump cycle may
be similar to the first, second, or third heat pump cycles
described above. The controller may then calculate a fourth flow
rate according to the variables stored during the fourth heat pump
cycle. The controller may then compare the calculated fourth flow
rate to the second reference flow rate and calculate a difference
between the two (e.g., a threshold percentage difference). In other
words, the calculated fourth flow rate may be stored as a certain
percentage of the second reference flowrate. From the comparison
(e.g., according to the calculated difference), a determination may
be made as to whether the fourth flow rate is within a
predetermined threshold (e.g., a certain threshold percentage)
relative to the second reference flow rate. Optionally, the
predetermined threshold may be a percentage of 50% of the (e.g.,
second) reference flow rate.
If the calculated fourth flow rate is less than the second
reference flow rate by the predetermined threshold, the controller
may stop the fourth heat pump cycle (i.e., stop a circulation of
the refrigerant). Thus, the fourth heat pump cycle may be
restricted or stopped in response to a determination that the
fourth flow rate is less than the predetermined threshold (e.g.,
threshold percentage). Additionally or alternatively, the
controller may initiate a new or second defrost cycle (e.g.,
subsequent to the fourth heat pump cycle being stopped or otherwise
in response to the determination that the fourth flow rate is less
than the predetermined threshold). The second defrost cycle may be
similar to the first defrost cycle described above.
Although four heat pump cycles are described above, it should be
understood that any number of heat pump cycles may be initiated and
performed, and any amount of reference flow rates may be calculated
and stored in accordance with the current disclosure.
This written description uses examples to disclose the invention,
including the best mode, and also to enable any person skilled in
the art to practice the invention, including making and using any
devices or systems and performing any incorporated methods. The
patentable scope of the invention is defined by the claims, and may
include other examples that occur to those skilled in the art. Such
other examples are intended to be within the scope of the claims if
they include structural elements that do not differ from the
literal language of the claims, or if they include equivalent
structural elements with insubstantial differences from the literal
languages of the claims.
* * * * *